Design of a differential relay for 1000-kV transmission line using MATLAB

This paper proposes a detail theory about the working principle of a current differential relay design for a 1000-kV transmission line. Normally the Voltage level of transmission lines is up to 500 kV or higher. If any kind of internal fault occurs on such type of transmission line will cause the major damage to the transmission quality of the line. So protection schemes for such cases must activate as rapidly as possible to minimise the damage to entire system. The differential protection is one of the main protections of the transmission line which trip instantaneously under fault condition. The simulation results of MATLAB show that the designed relay can be used as a main protection scheme for the 1000-kV transmission line.